7 so­lar fea­tures

From sunspots to so­lar fares, here’s our pick of the Sun sights to look for

Sky at Night Magazine - - EXPLAINER -

PROMI­NENCES

Vis­i­ble on the so­lar limb, promi­nences are dense erup­tions of plasma thrown out­ward from the chro­mo­sphere along mag­netic field lines.

PHO­TO­SPHERE

As the Sun is gaseous, we re­fer to the pho­to­sphere as the Sun’s sur­face. This is the area where light is re­leased and where sunspots and fac­u­lae can be seen.

FILAMENTS

Seen as dark lines across the so­lar disk, filaments are the same hy­dro­gen/al­pha fea­ture as so­lar promi­nences but viewed head on rather than ex­tend­ing side­wise into space.

CHRO­MO­SPHERE

A thin layer of so­lar at­mos­phere ex­ists above the pho­to­sphere and be­low the corona. Hy­dro­gen/al­pha fil­ters re­veal its promi­nences, filaments, plage and fares.

PLAGE

Plage is a fea­ture in the chro­mo­sphere, of­ten seen in as­so­ci­a­tion with sunspot groups. Plage can be an in­di­ca­tor of where a sunspot is about to form.

SUNSPOTS

Sunspots are caused by mag­netic fields cre­at­ing patches of cooler plasma. Sunspots have a dark cen­tral area, the um­bra, and a lighter outer area, the penum­bra.

SO­LAR FLARES

Mag­netic field lines break and re- con­nect, pro­duc­ing a re­lease of en­ergy. This event can be seen in hy­dro­gen/ al­pha as a bright­en­ing of the so­lar chro­mo­sphere.

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